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Title: (U) Detector Systems and Data Analysis for NDSE Experiments at the Dense Plasma Focus (DPF)

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [2]; ORCiD logo [1]
  1. Los Alamos National Laboratory
  2. P-21: APPLIED MODERN PHYSICS
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1419734
Report Number(s):
LA-UR-18-20830
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: NEDP2017 proceedings ; 2017-10-16 - 2017-10-20 ; Livermore, California, United States
Country of Publication:
United States
Language:
English

Citation Formats

Yuan, Vincent W. C, Boswell, Melissa, DeYoung, Anemarie, Fowler, Malcolm M., Goorley, John Timothy, Malone, Robert M., Morgan, George Lake, Obst, Andrew, and Rundberg, Robert S. (U) Detector Systems and Data Analysis for NDSE Experiments at the Dense Plasma Focus (DPF). United States: N. p., 2018. Web.
Yuan, Vincent W. C, Boswell, Melissa, DeYoung, Anemarie, Fowler, Malcolm M., Goorley, John Timothy, Malone, Robert M., Morgan, George Lake, Obst, Andrew, & Rundberg, Robert S. (U) Detector Systems and Data Analysis for NDSE Experiments at the Dense Plasma Focus (DPF). United States.
Yuan, Vincent W. C, Boswell, Melissa, DeYoung, Anemarie, Fowler, Malcolm M., Goorley, John Timothy, Malone, Robert M., Morgan, George Lake, Obst, Andrew, and Rundberg, Robert S. 2018. "(U) Detector Systems and Data Analysis for NDSE Experiments at the Dense Plasma Focus (DPF)". United States. doi:. https://www.osti.gov/servlets/purl/1419734.
@article{osti_1419734,
title = {(U) Detector Systems and Data Analysis for NDSE Experiments at the Dense Plasma Focus (DPF)},
author = {Yuan, Vincent W. C and Boswell, Melissa and DeYoung, Anemarie and Fowler, Malcolm M. and Goorley, John Timothy and Malone, Robert M. and Morgan, George Lake and Obst, Andrew and Rundberg, Robert S.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2018,
month = 2
}

Conference:
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  • Experimental evidences are presented for the formation of a closed, spheromak-like magnetic configuration (SLMC) by the plasma-focus-self-transformed magnetic field. The SLMC formation is characterized by (1) self-consistent generation of a poloidal magnetic fields (the dynamo effect); (2) strong filamentation of electric currents; (3) stimulating role of the enhanced propagation rate of the magnetic field along the anode, due to the Hall effect; (4) a magnetic field reconnection process leading to the formation of the SLMC as a closed configuration, appears to occur before the current sheath converges on the axis; (5) in its final stage, the SLMC takes the formmore » of a squeezed spheromak configuration compressed and forced away from the anode by the residual azimuthal magnetic field; (6) the power density in the combined Z {minus} {var_theta} pinch at major axis of the SLMC exceeds, by several orders of magnitude, the peak power density in the experiments on the force-free flux-conserver-confined spheromak; (7) the SLMC exhibits a cyclical tendency to form, be repelled from the anode, and reform repeatedly. The results suggest a possibility of further concentrating the plasma power density by means of compressing the SLMC-trapped plasma by the residual magnetic field.« less
  • Experimental results are presented which verify the possibility of the self-generated transformation of the magnetic field in plasma focus discharges to give a closed, spheromak-like magnetic configuration (SLMC). The energy conversion mechanism suggests a possibility of further concentrating the plasma power density by means of natural compressing the SLMC-trapped plasma by the residual magnetic field of the plasma focus discharge.
  • A 1.4-kJ ultra-clean Mather-type dense plasma focus has produced 14-MeV neutrons on 650 consecutive shots without a misfire and without purging the gas. The average D-T neutron output was (3.4 +- 0.8) /times/ 10/sup 9/ neutrons per shot. The D-T neutron pulse was used to calibrate fast-scintillator, photomultiplier neutron detectors. 14 refs., 3 figs., 1 tab.
  • Rockford Technology Associates, Inc. (RTA) has been doing experiments on the Dense Plasma focus (DPF) device at the Fusion Studies Laboratory of the University of Illinois. This DPF consists of four racks of five 2-{mu}F capacitors whose charge is switched onto the inner electrode of a plasma focus by four Trigatron spark gaps. The stored energy is 12.5 kJ at 25 kV. The bank is usually discharged in a static fill of H{sub 2} at {approx} 6 torr. Preliminary experiments aimed at exploring the potential of the DPF device as a magnetoplasmadynamic (MPD) thruster and as an x-ray source formore » lithography have investigated various alternative ways of injecting gas between the electrodes. One of those approaches consists of injecting gas from the tip of the inner electrode at a steady rate. In this operation, the DPF chamber pressure was held constant by running the vacuum pump at full throttle. This operation simulated simultaneous pulsed injection at the base insulator and electrode tip. Hydrogen was fed through a 1/16th-inch hole at a flow rate of {approx} 90 cm/s. Pulsing was then performed at 23 kV, and the corresponding variations of the current were observed using a Rogowski coil. It is found that the plasma collapses into a pinch at the same time as in conventional experiments using a static fill. The singularity in the current waveform is slightly smaller with tip injection, but its size and shape are easily reproducible. Further details and comparison of this operation with conventional pulsing will be presented.« less
  • Research on this grant has focused on plasma focus experiments in the areas of particle-beam generation and as a potential repetitive opening switch. In pursuing the former, unique diagnostic tools were developed to measure the scaling of particle-beam current and energy for both the electron and ion beams generated by the device. Simultaneous measurements of the energy spectra for both the electron and ion beams were measured for the first time as were scaling laws for the increase of electron energy and current with input energy. The potential of the plasma focus as an opening switch was then investigated. Measurementsmore » of the current and voltage waveforms indicated that the resistance of the pinch was roughly ten times the classical value estimated from electron-temperature measurements and streak pictures. To increase the efficiency the impaler concept was devised which could have a transfer efficiency of well over 50% according to the results of a physical model. The frequency of the microwave emission was measured using the delay line technique. The observed frequencies were most consistent with the lower hybrid frequency.« less